Endocrine Abstracts

Aim of the work: In patients with differentiated thyroid cancer, the basic goal of the therapy is to improve overall and disease-specific survival, reduce the risk of persistent/recurrent disease while minimizing treatment-related morbidity and unnecessary therapy. In 2015, the American Thyroid Association (ATA) published evidence-based guidelines for the staging and management of differentiated thyroid cancer, including the possibility of avoiding systematic complementary 131-iodine therapy in low-risk patients. Based on these new recommendations, we have modified our management, treatment and monitoring of thyroid carcinoma. The current study aimed at evaluating the influence of these modifications on the therapeutic efficacy in patients with thyroid cancer before and after 2015.

Methods: We conducted a retrospective study in a cohort of patients diagnosed and treated at the Brugmann Hospital between 2007 and 2017. A few patients with metastatic disease were treated several times. Patients were divided into two groups: before (Group 1) and after 2015 (Group 2). We compared the two groups in terms of general characteristics, risk of recurrence (based on the 2015 ATA recommendations), cumulative administered 131-iodine activity and biological and morphological response to therapy. Due to the repeated treatment in some patients, the distribution of cumulative activity was not Gaussian.

Results: A total of 98 patients were included: 53 in Group 1 and 48 in Group 2, with a mean age of 50 vs 43 years. Both groups were different in terms of risk stratification: in Group 1, 37.7% were classified as low risk, 45.3% as intermediate risk and 17% as high risk. These figures were respectively 16.7%, 54.2% and 29.2% in Group 2 (P=0.048). The median cumulative activity of 131-iodine was significantly higher in group 1 (3700MBq, range 1110–14800 MBq) than in group 2 (1110 MBq, range 1110–20350 MBq), P=0.000012. Excellent response, meaning no clinical, biological or morphological evidence of residual/recurrent disease, was found in 90.5% in Group 1 vs. 89.5% in Group 2 (P=0.347).

Conclusions: The publication of the ATA evidence-based guidelines for the staging and management of differentiated thyroid cancer in 2015 modified our therapeutic management. After 2015, although the number of patients with a high risk of recurrence was greater and the median administered 131-iodine activity significantly lower, including no systematic iodine administration in low-risk patients, the rate of excellent therapeutic response remained unchanged.